Proposed Format - ITU · Web viewlong_nom real 8 Yes The satellite nominal orbital longitude, in degrees, and in the range -180 to 180 degrees. The format used for this parameter

Attachment 2 to Circular Letter CR/58

Description of the format for electronic submission of graphical data related to satellite networks

Table of Contents

1. Introduction

2. Overall Description and Definitions

3. The [FormatInfo] Section

4. Geostationary Satellite Networks Graphical Data - Formal Description

4.1 General

4.2 The [GeoMain] section

4.3 Description of a Gain Contours Diagram4.3.1 The [COHeader] section4.3.2 The [Bi] sections4.3.3 The [Ci] sections

4.4 Description of a Service Area Diagram4.4.1 The [SAHeader] section4.4.2 The [SRi] sections

4.5 Description of a Gain towards the GSO Diagram4.5.1 The [GSOHeader] section4.5.2 The [GSODiag] section

4.6 Description of an Earth Station Antenna Radiation Pattern4.6.1 The [EPDHeader] section4.6.2 The [EPDDiag] section

5. File Naming

Annex A - Index of used keywords

Annex B - Sample files for gain contours diagrams 26

Annex C - Sample files for service areas diagrams 38

Annex D - Sample files for gain/GSO diagrams 42

Annex E - Sample files for EPD diagrams 46

Annex F - Sample file containing multiple diagrams 48

Attachment 2 to Circular Letter CR/58 October 1996page 1

1. Introduction

The purpose of this document is to describe a file format that can be used to allow the submission of graphical data related to satellite networks in electronic form, and then the processing of this data in order to incorporate it in the different BR data bases (mainly, GIMS and GIMROC).

In its current version (no 1), the format described in this document concerns the submission of the graphical data only related to geostationary satellite networks. Future versions will deal with both geostationary and non-geostationary satellite networks.

2. Overall Description and Definitions

The format described in this document is based on the format of Windows initialization (*.INI) files. Therefore, it is a text format (in ASCII), based on the idea of structuring the file into several sections, where each section is identified by a section name and includes a set of entries, where each entry consists of a string identifier called key, followed by the value of the related parameter, separated from its key with the = sign.

Each section name is encapsulated between square brackets and written on a single line. Each entry (of the form “key=value”) is written on a single line. Line separator is assumed to be carriage return and line feed (CR+LF).

Thus, the overall aspect of a file following this format and containing N sections is the one shown in Figure 1 below.

[SectionName1]key1=value1key2=value2key3=value3........................[SectionName2]key1=value1key2=value2key3=value3........................[SectionNameN]key1=value1key2=value2key3=value3........................

FIGURE 1

Overall Aspect


3. The [FormatInfo] Section

The format described in this document is intended to be subject to further additions, modifications and enhancements in order to meet future requirements. Thus, it is expected that, in some future time, several versions of this format will become available for submission of the graphical data. It will then be essential that the processing software ensures backward compatibility and operates the proper processing of the submitted files, according to the version of the format that has been used to produce them.

Therefore, at the top of the file is a mandatory section entitled [FormatInfo] where the needed version information appears. Currently, this section contains only one entry, but it is likely to be expanded later.

Section Name:

[FormatInfo]

Purpose: This section contains global information about the format version used in the file. There must be one and only one [FormatInfo] section in the file.

Entries:

Key Type Maximum Length

Mandatory Meaning and Format

format_ver int 2 Yes The version number of the format used in the file.

Currently, the only available version number is 1. Therefore, the value of this parameter must be 1

4. Geostationary Satellite Networks Graphical Data - Formal Description

This section formally describes the use of the above defined format as a mean to submit and/or produce files describing graphical data for geostationary satellite networks. This data mainly involves description of the following diagram types:

- Space station antenna gain contours on the Earth’s surface.- Space station antenna service area outlines on the Earth’s surface.- Space station antenna gain towards the geostationary orbit (GSO).- Earth station antenna radiation pattern (gain polar diagram).

4.1 General

A given file may include one or more diagrams related to the same satellite network. Therefore, immediately after the [FormatInfo] section is a section called [GeoMain] which includes this information, together with other information globally used in the file such as the satellite orbital longitude, the number of diagrams contained in the file, the notifying administration code, etc..

The representation of each diagram consists of a mandatory header section, marking the start of a new diagram description, and where the identifying elements appear (the beam designation, the emission/reception flag, etc.). The header section name and layout vary depending on the type of the described diagram. It is then followed by several sections describing the diagram according to its type. Gain contours and service areas diagrams are mainly described in the form of geographical points on the Earth’s surface. Gain/GSO diagrams are described in the form of Cartesian (gain;longitude) points. Earth station antenna polar diagrams are described in the form of polar (gain;theta) points.


The adopted representation for the geographical coordinates is longitude;latitude, in degrees, as signed real numbers in decimal notation, with 3 significant digits to the left of the decimal point for longitude, 2 significant digits to the left of the decimal point for latitude and 3 significant digits to the right of the decimal point. The decimal point character that should be used is (.), and a semicolon (;) is used as a separator between longitude and latitude. Longitudes are assumed to be in the range -180 to 180 and latitudes are assumed to be in the range -90 to 90. West longitudes and South latitudes are considered to be negative. East longitudes and North latitudes are considered to be positive. Therefore, the general format used to represent the geographical coordinates of a given point on the Earth’s surface is:

{sxxx.xxx;sxx.xxx

longitude latitude

{

where s refers to the sign character which can be either + or -. If the sign is omitted here, it is considered to be positive (+).

The adopted representation for the gain values (when needed) is gain in dB, as signed real numbers in decimal notation, with 2 significant digits to the left of the decimal point and 2 significant digits to the right of the decimal point. The decimal point character that should be used is (.). Therefore, the general format used to represent the gain values is:

sxx.xx

where s refers to the sign character which can be either + or -. If the sign is omitted here, it is considered to be positive (+).

The following paragraphs describe the details of each section in the file and specify the names used for sections and keys. These are to be considered as keywords and should only be used in the file according to their specified meaning.

Certain key elements that appear in this document are also present on the Appendix 3 (Appendix S4) notice form. These elements are used to establish the correspondence between the alphanumeric data on the notice form and the graphical data. It is therefore essential that these elements are exactly the same on the notice form and in the file containing the graphical data.

When appropriate, this document also indicates if a given entry is mandatory or optional and gives the set of allowed values for a given parameter, together with their meanings, as well as an indication about the maximum number of characters (string length) that is taken into account when applicable.

For some count parameters (such as number of diagrams, number of points, ...), this document also indicates the maximum allowed values. However, these limitations are currently needed only for compatibility purposes with the existing storage system. It is expected that in later versions no limitations will be applicable anymore.

In the following paragraphs, the following abbreviations are adopted when indicating the types of parameters:

char: character stringint: integer valuereal: real valuegeo coord: geographical coordinates (longitude;latitude)

In addition, where the term “relative gain” is used, it designates the gain value in dB relative to the maximum gain. The relative gain values are negative.


4.2 The [GeoMain] section

Section Name:

[GeoMain]

Purpose: This section contains global information about the file, as well as some global parameters used along the file. There must be one and only one [GeoMain] section in the file.

Entries:



adm char 3 Yes The notifying administration 3 characters code, according to Table No. B1 in the Preface.

ntwk_org char 3 No The symbol of the responsible organization operating regional or international satellite networks, (see Table No B2 in the Preface).

sat_name char 20 Yes The name of the satellite network to which the file is related.

long_nom real 8 Yes The satellite nominal orbital longitude, in degrees, and in the range -180 to 180 degrees.The format used for this parameter is sxxx.xxx, where s is the sign character.

n_diag int 2 Yes The number of diagrams described in the file. This number should correspond to the number of header sections appearing in the file.

The maximum allowed value for this parameter is 99.

Example:

The following [GeoMain] section indicates that the file includes descriptions for 1 diagram, notified by USA for the ACS-1 satellite, having its nominal orbital position at 100 degrees West.

[GeoMain]adm=USAsat_name=ACS-1long_nom=-100.000 (or long_nom=-100)n_diag=1

FIGURE 2


4.3 Description of a Gain Contours Diagram

The description of a gain contours diagram consists of several sections, specifying the associated header elements, the boresights data and gain contours data. In this context, the word boresight(s) is used to designate the point(s) of maximum/peak gain, and should not be confused with the “aim point” of the related beam. The needed data is therefore composed by the number of boresights, the geographical coordinates and the relative gain value in dB for each boresight, the number of gain contours and, for each contour, the associated relative gain value in dB, the number of points forming the contour and the geographical coordinates of each point. This data is organized in the following sections as described below.

4.3.1 The [COHeader] section

Section Name:

[COHeader]

Purpose: The description of any gain contours diagram in the file always starts with a mandatory [COHeader] section. This section contains the elements that, together with the adm, sat_name and long_nom from the [GeoMain] section, uniquely identify the described diagram. In addition, this section contains counting fields, specifying the number of boresights and the number of contours. The layout of this section is described below.



beam_id char 4 Yes The designation of the satellite antenna beam.

For AP30, AP30A and AP30B Plans, this field should not be confused with the “beam identification” which uses a different naming convention ( 8 characters).

emi_rcp char 1 Yes The emission/reception flag at the space station. This parameter must have one of the following values:

E, for emission (down-link)

R, for reception (up-link)

polar_disc char 1 Yes The polarization discriminator. This parameter must have one of the following values:

C, for co-polarization

X, for cross-polarization


reason char 1 Yes The reason for notification. This parameter must have one of the following values:

A, for advance publication (RR1042, RES33, RES46)

C, for 1) request for coordination

(RR1060, RES33, RES46, Article 7 of AP30), OR

2) modification to BSS Plan AP30/30A, OR

3) modification to FSS Plan AP30B

E, for Article 14 procedure

N, for notification under1) RR1488 (Article 13), OR2) Article 5 of AP30/30A3) Article 7 of AP30

n_bore int 2 Yes The number of boresights related to the specified beam.


n_cont int 2 Yes The number of contours forming the diagram.


4.3.2 The [Bi] sections

Each boresight is described in the file in a section entitled [Bi] (where i is the index of the boresight (1<i<n_bore)), which contains the geographical coordinates and the relative gain value in dB at this boresight. The order in which the boresights are numbered is irrelevant, but the number of [Bi] sections must match the value of n_bore in the [COHeader] section.

Section Name:

[Bi]

Purpose: This section describes the i-th boresight (1<i<n_bore).

Entries:



gain real 6 No The relative gain level in dB at the i-th boresight. The used format is sxx.xx, where s is the sign character.

If this entry is omitted, the relative gain value at the boresight is considered to be 0dB.


p geo coord

16 Yes The geographical coordinates in degrees (longitude;latitude) of the i-th boresight. The format for this entry is sxxx.xxx;sxx.xxx, where s is the sign character.

4.3.3 The [Ci] sections

Each gain contour is described in the file in a section entitled [Ci] (where i is the index of the contour (1<i<n_cont)), which contains the associated gain value, the number of points forming the contour and the coordinates of these points. The order in which the contours are numbered is irrelevant, but the number of [Ci] sections must match the value of n_cont in the [COHeader] section.

It is important to note that the word "contour" is used here to designate a single set of consecutive geographical points, forming a single geographical line which can be either open or closed. In other words, if, for instance, the -2dB gain contour consists of two (or more) disjoint lines, a [Ci] section for each of these lines must appear in the file. This also applies to the value that should be given to the n_cont parameter in the previous section.

· When the described contour is a closed contour, the first specified point can be anywhere on the contour, and the last specified point must be the same point as the starting point in order to close the contour.

· When the contour is an open contour, the first specified point must be at one of the two ends, and the last specified point must be at the other end. In addition, the first and last specified points must be on the horizon seen from the space station.

However, in both cases, the sense of rotation of the contour (clockwise or anti-clockwise) is not relevant.

Section Name:

[Ci]

Purpose: This section describes the i-th contour (1<i<n_cont).

Entries



gain real 6 Yes The relative gain level in dB associated with this contour. The used format is sxx.xx, where s is the sign character.

n_point int 4 Yes The number of points forming the contour.


pn geo coord

16 Yes The geographical coordinates in degrees (longitude;latitude) of the n-th point. The format for this entry is sxxx.xxx;sxx.xxx, where s is the sign character.

There must be an entry of this type for each point. The index n takes integer values in the range 1<n<n_point.

The total number of points used to describe the complete set of contours in a given diagram (that is, the sum of the n_point parameter values in the different related [Ci] sections) must not exceed 4000.

< 4000

In terms of resolution, the density of the supplied points does not need to be uniform (no regular sampling step is required). That is, the specified points do not need to be equally spaced neither in longitude nor in latitude. The “resolution” of the supplied points may vary, depending on the complexity of the diagram part being described. It is the responsibility of the diagram provider to operate this resolution-complexity modulation, according to the desired accuracy.


Figure 4 below shows the overall aspect of the description of a gain contours diagram.

Annex B shows examples resulting from the application of the described format to several types of gain contours diagrams.

[COHeader]beam_id=emi_rcp=polar_disc=reason=n_bore=n_cont=

[B1]gain=p=

[B2]gain=p=

........

........

[C1]gain=n_point=p1=p2=p3=................

[C2]gain=n_point=p1=p2=p3=................

........

........

FIGURE 4

Overall aspect for gain contours description


4.4 Description of a Service Area Diagram

Antenna service area is assumed to be composed of one or more service regions, each of which may be defined by two different methods:

a) as discrete points, specifying one or more earth station locations represented by discrete (longitude;latitude) coordinates;

b) as a continuous contour, defining the outline of the service region, be it geographical (the boundaries of a given country, or the visible part of one of the three radiocommunication Regions) or a gain contour.

Therefore, the complete description of the service area consists in specifying the associated header elements, the number of service regions forming the service area, and then describing each service region in an independent section. This data is organized in the following sections as described below.

4.4.1 The [SAHeader] section

Section Name:

[SAHeader]

Purpose: The description of any service area diagram in the file always starts with a mandatory [SAHeader] section. This section contains the elements that, together with the adm, sat_name and long_nom from the [GeoMain] section, uniquely identify the described diagram. In addition, this section contains the number of service regions forming the service area. The layout of this section is described below.

Entries:




For AP30, AP30A and AP30B Plans, this field should not be confused with the “beam identification” which uses a different naming convention ( 8 characters).







C, for 1) request for coordination

(RR1060, RES33, RES46, Article 7 of AP30), OR




N, for notification under

1) RR1488 (Article 13), OR2) Article 5 of AP30/30A3) Article 7 of AP30

srv_area char 20 Yes The service area name.

area_no int 2 Yes The service area number.

The first service area number should be 1 and, in the case where there are many different service areas associated with a given satellite antenna beam, these additional service areas should be numbered consecutively (2, 3, 4, etc.).

On the Ap3/ApS4 notice form, the field “Service Area Number” relating to the service area for the group of frequencies operating in the beam in question must contain the corresponding service area number as contained in this file.


n_rgn int 2 Yes The number of service regions forming the service area.



4.4.2 The [SRi] sections

Each service region is characterized by a service region name, a flag indicating whether it is a discrete region or not, the number of points forming this region and, finally, the geographical coordinates of these points on the Earth’s surface. These elements are grouped in a section entitled [SRi], where i is the index of the service region (1<i<n_rgn). The order in which the service regions are numbered is irrelevant, but the number of [SRi] sections must match the value of n_rgn in the [SAHeader] section.

Section Name:

[SRi]

Purpose: This section describes the i-th service region (1<i<n_rgn).

Entries:Key Type Maximum

LengthMandatory Meaning and Format

rgn_name char 20 Yes The name of the service region.discrete char 1 No This is a flag indicating whether the

service region is discrete or not. It must have one of the following values:

Y, the service region is discrete

N, the service region is not discrete.

If this entry is omitted, the service region is considered to be continuous (not discrete)

n_point int 4 No(see below)

The number of points forming the service region outline.

pn geo coord

16 No(see below)

The geographical coordinates in degrees (longitude;latitude) of the n-th point. The format for this entry is sxxx.xxx;sxx.xxx, where s is the sign character.


· When the outline of a given service region is specified as a contour, it must be a closed contour , and needs to be closed by the horizon seen from the space station (when applicable). In this case, the n_point and pn entries are mandatory.

· When the outline of a given service region is the political boundaries of a given country, it can be automatically retrieved from the IDWM (ITU’s Digitized World Map). In order to achieve this, the service region name must consist of the “IDWM:” prefix, followed by the desired (3 characters) country code. The service region is considered by default to be the complete political boundaries of the specified country, and the n_point and pn entries are not needed and can be omitted. When only a part of the specified country is to be considered as the service region outline, two geographical points must be specified (n_point=2): these points respectively define the lower left and upper right corners of the “geographical window” inside which the political boundaries of the specified country are to be considered as the service region outline.


· When the outline of a given service region is the visible part of one of the three radiocommunication Regions, it can also be automatically retrieved from the IDWM. In order to achieve this, the service region name must consist of the “IDWM:” prefix, followed by one of the following 3 characters code for the desired Region:

RG1 for Region 1RG2 for Region 2RG3 for Region 3.

In this case as well, the service region is considered by default to be the complete specified Region, and the n_point and pn entries are not needed and can be omitted. When only a part of the specified Region is to be considered as the service region outline, two geographical points must be specified (n_point=2): these points respectively define the lower left and upper right corners of the “geographical window” inside which the outlines of the specified Region are to be considered as the service region outline.

Thus, the service region name IDWM:RG2, for instance, indicates that the service region outline is the visible part of the radiocommunication Region 2.

The total number of points used in the file to describe a complete service area diagram (that is, the sum of the n_point parameter values (when specified) in the different related [SRi] sections) must not exceed 4000.

< 4000

In terms of resolution (when the service region outline is supplied as a contour), the density of the supplied points does not need to be uniform (no regular sampling step is required). That is, the specified points do not need to be equally spaced neither in longitude nor in latitude. The “resolution” of the supplied points may vary, depending on the complexity of the diagram part being described. It is the responsibility of the diagram provider to operate this resolution-complexity modulation, according to the desired accuracy.


Figure 5 below shows the overall aspect of the description of a service area diagram.

Annex C shows examples resulting from the application of the described format to several types of service areas diagrams.

[SAHeader]beam_id=emi_rcp=reason=srv_area=area_no=n_rgn=

[SR1]rgn_name=discrete=n_point=p1=p2=p3=p4=p5=................

[SR2]rgn_name=IDWM:RG2

[SR3]rgn_name=IDWM:TUN

[SR4]rgn_name=IDWM:ALGn_point=2p1=-7.500;18.984p2=11.986;35.000

........

........

FIGURE 5

Overall aspect for service area description


4.5 Description of a Gain towards the GSO Diagram

The satellite antenna gain to the GSO diagram shows the gain of the satellite antenna in the direction of the geostationary orbit (those points which are not obscured by the Earth), as a function of the orbital longitude. We refer to this diagram type as GSO.

Therefore, this diagram consists of an orthogonal axis pair, with linear gain scale along the y axis and a continuous linear orbital longitude scale along the x axis. The orbital longitude axis should cover a full 360 degrees range and increases eastwards.

The antenna gain/GSO versus orbital longitude diagram is stored as a series of (gain;longitude) coordinates. The west part of the diagram is taken to be the part with the lower orbital longitude values.

The figure below shows the typical aspect of this diagram with West and East parts bounding the zone obscured by the Earth (relative to the considered satellite). However, this general aspect may be different if the obscured part is placed on the axes intersection point (origin). This can be implemented through simple geometrical transformation (e.g., axes translation).

FIGURE 6

Therefore, the complete description of the Gain/GSO diagram consists in specifying the boundaries of the diagram (minimum and maximum gain and minimum and maximum longitude) and then describing the diagram as a series of (gain;longitude) points. This data is organized in the following sections as described below.


4.5.1 The [GSOHeader] section

Section Name:

[GSOHeader]

Purpose: The description of any Gain/GSO diagram in the file always starts with a mandatory [GSOHeader] section. This section contains the elements that, together with the adm, sat_name and long_nom from the [GeoMain] section, uniquely identify the described diagram. In addition, this section contains the boundaries of the diagram. The layout of this section is described below.

Entries:




For AP30A Plan, this field should not be confused with the “beam identification” which uses a different naming convention ( 8 characters).




polar_disc char 1 Yes The polarization discriminator. This parameter must have one of the following values:





C, for

1) request for coordination (RR1060, RES33, RES46) OR2) modification to BSS Plan AP30A



1) RR1488 (Article 13), OR2) Article 5 of AP30A


min_bound_gain real 6 Yes The minimum gain value in dB, used in the diagram (see the figure above).The format for this entry is sxx.xx, where s is the sign character.

max_bound_gain real 6 Yes The maximum gain value in dB, used in the diagram (see the figure above).The format for this entry is sxx.xx, where s is the sign character.

min_bound_long real 8 Yes The minimum orbital longitude used in the diagram (see the figure above), in degrees.The format for this entry is sxxx.xxx, where s is the sign character.

max_bound_long real 8 Yes The maximum orbital longitude used in the diagram (see the figure above), in degrees.The format for this entry is sxxx.xxx, where s is the sign character.

4.5.2 The [GSODiag] section

Section Name:

[GSODiag]

Purpose: This section contains the data describing the GSO diagram, as a series of (gain;longitude) points.

Entries:



n_point int 4 Yes The number of points forming the GSO diagram.

pn coord 15 Yes The Cartesian coordinates (gain;longitude) of the n-th point in the diagram. The longitude is expressed in degrees, and the gain is expressed in dB. The format for this entry is sxx.xx;sxxx.xxx, where s is the sign character.


The total number of points used in the file to describe a complete Gain/GSO diagram (that is, the value of the n_point parameter in the [GSODiag] section) must not exceed


4000.

n_point < 4000

In terms of resolution, the density of the supplied points does not need to be uniform (no regular sampling step along the orbital longitude axis is required). That is, the specified points do not need to be equally spaced in the interval min_bound_long to max_bound_long. The “resolution” of the supplied points may vary, depending on the complexity of the diagram part being described. It is the responsibility of the diagram provider to operate this resolution-complexity modulation, according to the desired accuracy.

Figure 7 below shows the overall aspect of the description of a Gain/GSO diagram.

Annex D shows examples resulting from the application of the described format to Gain/GSO diagrams.

[GSOHeader]beam_id=emi_rcp=polar_disc=reason=min_bound_gain=max_bound_gain=min_bound_long=max_bound_long=

[GSODiag]n_point=p1=p2=p3=p4=p5=................

FIGURE 7

Overall aspect for Gain/GSO description


4.6 Description of an Earth Station Antenna Radiation Pattern

The earth station antenna radiation pattern should normally be described by a reference to a standard pattern such as REC-465, REC-580, AP28, AP29 or 32-25 LOG(FI), etc. However, an Administration that wishes to use an antenna radiation pattern that is significantly different from any of the standard patterns may submit a polar diagram that represents the antenna gain as a function of the off-axis angle. An example is given in Figure 8 below. The preferred way of submitting this information is by reference to a standard pattern and the graphical method is to be used only in exceptional cases.

FIGURE 8

It is important to note that the gain at the center of the diagram is the minimum gain used in the diagram.

Therefore, the complete description of the earth station antenna pattern consists in specifying the associated header elements, the bounding gain values used in the diagram (center_gain and edge_gain on the figure above), and then describing the diagram as a series of consecutive (gain;theta) points. This data is organized in the sections described below.


4.6.1 The [EPDHeader] section

Section Name:

[EPDHeader]

Purpose: The description of any earth station antenna radiation diagram in the file always starts with a mandatory [EPDHeader] section. This section contains the elements that, together with the adm, sat_name and long_nom from the [GeoMain] section, uniquely identify the described diagram. In addition, this section contains the boundaries of the diagram. The layout of this section is described below.

Entries:




For AP30, AP30A and AP30B Plans, this field should not be confused with the “beam name” which uses a different naming convention ( 8 characters).




polar_disc char 1 Yes

(AP30/30A only)

The polarization discriminator. This parameter must have one of the following values:





C, for

1) request for coordination (RR1060, RES33, RES46), OR





1) RR1488 (Article 13), OR2) Article 5 of AP30/30A


e_stn_name char 20 Yes The name of the related earth station.

center_gain real 6 Yes The gain value in dB, at the center of the diagram (which is the minimum gain value used in the diagram. See the figure above).The format for this entry is sxx.xx, where s is the sign character.

edge_gain real 6 Yes The gain value in dB, at the edge of the diagram (which is the maximum gain value used in the diagram. See the figure above).The format for this entry is sxx.xx, where s is the sign character.

4.6.2 The [EPDDiag] section

Section Name:

[EPDDiag]

Purpose: This section contains the data describing the earth station antenna radiation diagram, as a series of (gain;theta) points.

Entries:



n_point int 4 Yes The number of points forming the diagram.

pn coord 14 Yes The polar coordinates (gain;theta) of the n-th point in the diagram. The off-axis angle is expressed in degrees and in the range 0 to 360, and the gain is expressed in dB.

The format for this entry is sxx.xx;xxx.xxx, where s is the sign character.


The total number of points used in the file to describe a complete earth station antenna radiation diagram (that is, the value of the n_point parameter in the [EPDDiag] section) must not exceed 4000.

n_point < 4000


The supplied points must cover the full 0 to 360 degrees range, starting at 0 (where the maximum antenna gain occurs). However, in terms of theta values, the density of points does not need to be uniform (no regular theta-step is required). That is, the specified points do not need to be equally spaced in the interval 0 to 360 degrees. The “theta-resolution” of the supplied points may vary, depending on the complexity of the diagram part being described. When the diagram comprises complex sidelobes, for instance, the theta-resolution used to describe these sidelobes could be higher than the theta-resolution used to describe the more regular parts of the diagram (such as the main lobe, for example). It is the responsibility of the diagram provider to operate this resolution-complexity modulation, according to the desired accuracy.

On the other hand, it is possible to specify a constant gain value in a given interval of angles. This can be achieved by specifying the first point in the interval, immediately followed by the last point in the interval. In other words, when the gain value is G for all angles between theta1 and theta2, the following syntax must appear in the diagram description:

.......

.......pn=G;theta1pn+1=G;theta2..............

Figure 9 below shows the overall aspect of the description of an earth station antenna radiation diagram.

Annex E shows examples resulting from the application of the described format to earth station antenna radiation diagrams.

[EPDHeader]beam_id=emi_rcp=polar_disc=reason=e_stn_name=center_gain=edge_gain=

[EPDDiag]n_point=p1=gmax;0p2=p3=p4=p5=................

FIGURE 9

Overall aspect for earth station antenna radiation diagram description


5. File Naming

When the graphical data is submitted electronically, according to the format described in this document, the files containing this data must be named according to DOS files naming conventions. That is, the file names must have the following format:

name.ext

where

name is the name of the file which can be up to 8 charactersext is the (optional) extension of the file which can be up to 3 characters.

Although no mandatory rules are needed for names and extensions, it is strongly recommended to conform to the following:

1) Use “.GXT” as the file extension. This extension stands for “Graphical External”.2) Whenever possible, let the notifying Administration 3 characters code be a prefix in the name

part of the file name.

Examples of recommended file names are:

USAFILE.GXT ; FSUBMIT.GXT ; RUSTOITU.GXT.


Annex A Index of used keywords

This annex summarizes the list of keywords used in the description of graphical data, according to the format described in this document.

—A—adm, 5area_no, 12

—B—B, 7beam_id, 6; 11; 17; 21

—C—C, 8center_gain, 22COHeader, 6

—D—discrete, 13

—E—e_stn_name, 22edge_gain, 22emi_rcp, 6; 11; 17; 21EPDDiag, 22EPDHeader, 21

—F—format_ver, 3

—G—gain, 7; 8GeoMain, 5GSODiag, 18GSOHeader, 17

—I—IDWM, 13

—L—long_nom, 5

—M—max_bound_gain, 18max_bound_long, 18min_bound_gain, 18min_bound_long, 18

—N—n_bore, 7n_cont, 7n_diag, 5n_point, 8; 13; 18; 22n_rgn, 12ntwk_org, 5

—P—p, 8; 9; 13; 18; 22polar_disc, 6; 17; 21

—R—reason, 7; 12; 17; 21rgn_name, 13

—S—SAHeader, 11sat_name, 5SR, 13srv_area, 12


Documents

Proposed Format - ITU · Web viewlong_nom real 8 Yes The satellite nominal orbital longitude, in degrees, and in the range -180 to 180 degrees. The format used for this parameter